When I first started trying to use my Juki industrial machine, I had a major problem with the machine's speed. My Juki has a clutch motor, and it was set up to sew too fast for me. The treadle on a clutch motor equipped machine doesn't provide for much speed control at all - it's more like an on-off switch. The treadle basically just engages or disengages the clutch - that's it. While you can "slip" the clutch a bit to get you started, that builds up a lot of heat and can eventually damage the clutch.

I quickly found out that I wasn't the only one who had this problem. DanTwoLakes, Hotrodders' resident upholstery guru and moderator to the stars, told us how to solve the problem by doing a simple motor pulley swap.

Probably the most commonly suggested fix for this type of thing is to replace the clutch motor with a servo motor that has variable speed control. That's fine if you have the money to invest (and it is a good investment,) but what if you're a mope like me who doesn't have the $180 to spend on a new motor right now? The answer is to change out the pulley on the clutch motor for a smaller pulley.

Yes, a smaller one. I know that some are saying that a smaller pulley will make the machine run faster. People immediately think of a 10-speed bicycle - you move the chain down to the smaller pulley on the rear sprocket to make the bicycle go faster. That's true - but when you do that, do you suddenly start pedaling faster or slower? That's the point. Think instead of the FRONT sprockets on a 10-speed. When you move the chain down to the smaller front sprocket, you pedal faster, but move slower.

To sum up this point, it's all in where you provide the power, not in where the power ends up. If the chain on our imaginary bicycle is on the smaller front sprocket (where we provide the power) the bike moves at a slow speed. If we move the chain up to the larger sprocket and pedal at the same speed, the bike moves faster. Conversely, if we move the chain down to the smaller sprocket and pedal at the same speed, the bike moves slower. The same is true with the pulleys on the sewing machine. The motor spins at the same RPM no matter what size pulley it has on it. By switching down to the smaller pulley, the machine will run slower.

Keep in mind that when you swap pulleys, you'll also have to get a smaller belt. In my case I swapped out the 3 1/2 inch diameter motor pulley for a 1 3/4 inch diameter pulley, and swapped from the 45 inch belt to a 42 inch belt. It slowed down the machine considerably, and gave me better control all around. You most likely won't get the exact belt you need on the first try. Luckily the hardware store I went to let me exchange the belt with no problem. The motor can be adjusted to take up some slack, much in the same way you would tighten the belt on an alternator or similar, but it won't take out much more than an inch of slack.

Here's a video I found that demonstrates how to slow down the speed on your industrial sewing machine with a clutch motor by swapping out the pulley on the motor, changing the belt, and adjusting the belt tension.

The guy who shot this video is in Mexico, and he's done several upholstery videos. He uses subtitles to communicate, and there are a few typos, but you will get what he's saying. I've found that I have to pause the video in spots to read the subtitle - you'll see what I mean.

I got my pulley and belt at my local hardware store, and the whole modification cost less than $20. The two things you need to know going into the store is the shaft size on your motor (most are 1/2 inch or 3/4 inch) and the belt width. I took my old belt in with me and matched the pulley width to the old belt, then matched the width of the new belt to the new pulley. Have some idea as to how small a pulley you want to get, but remember that the smaller you go, the slower your machine will run. I went with a 1 3/4 inch diameter pulley, but I probably could have gone smaller - maybe 1 1/4 or 1 1/2 inch diameter. I'm used to this set-up now, so it doesn't matter to me anymore, but your mileage may vary.

No matter how small of a pulley you swap down to, keep the old pulley and belt, just in case you want to change them back some time down the road.

In summary, a smaller pulley on your clutch motor will slow down your industrial sewing machine, giving you better control, and improve the quality of your work - all for about $20. It's a great modification to your machine for those who are learning to sew or just starting out and can't immediately afford to upgrade to a servo motor with variable speed control.

I have the tools to do this. I have a puller that looks just like the video. Ball pien hammer rather than a claw hammer. Looks more 'Pro" The 'lock channels...to the old guys it is a waterpump pliers. I have some narrow head combination wrenches as well as a 'thinned' adjustable wrench. If the motor shaft is U.S. it should go pretty easy. McMaster has some round belts but it looks like the V belt will work too. I usually make a guess on the belt length then get 4 of them at the parts store and bring all but one back.

I saw a used servo motor last week but it's already gone.

Are thesse clutches a 'dog' style or a 'slippable one like a car clutch.

Too bad they don't make a mini Crowerglide. haha That I would understand.

The snow is finally melting, looks like rain. We really need it to wash the salt awway. I may go for a cruise at least to fill up the tank.

A clutch motor for a sewing machine simply engages and disengages the machine head from the motor. You can slip the clutch with the foot pedal to make the machine go slower, but the motor itself is always running at full speed.

The belt should be a "V" belt. I prefer a 3VX belt that is cogged, but it doesn't matter.

Do you know how to measure for belt size? Measure from the center of the motor's shaft to the center of the shaft the pulley is mounted on on your sewing machine. Say that's 13". Double it to make 26". Then measure the diameters of the pulley on the machine and the pulley on the motor. Say the machine has a 5" pulley and the motor has a 4" pulley. Multiply the two diameters by PI, divide each one by two and add the three dimensions together. In this case, 3.1417 times 5 divided by two equals 7.85 inches and times 4 divided by two equals 6.28". Add 26" plus 7.85" plus 6.28" and you get 40.13" You'd use a 40" belt in this example.

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I didn'tmean to dredge up an old thread. I had several open and hooked the wrong one. At least the clutch stuff will stay together so it can be searched.

Thanks for the info. That should get close. Looks like there is a lot of room for adjustment on the videos.

I'll try and get the 'cog' belts. I like them too for other belts too.

I should have kept my mouth shut about this machine at the shop. I guess I was just too excited. haha So now I hear "Now you can make this...and that for us". I barely know where the 'on/off' switch is let alone how to run the machine. I've been working on their race cars for the last 6 months now it is time for my car. I finished the very last of their racer projects today. I need a break to do something fun.

I have looked at a lot of big machines, never owned one really but it always looks like a problem to me. My brother in law bought a big industrial Juki sweat shop machine and quickly found out it was totally unsuitable for what he wanted, way too fast. I have been thinking a lot about a way to control the speed on one. A rheostat controlled motor is one choice but they never seem to have much power on slow. Another Idea I had would be a sort of transmission that had a rubber tire running on a spinning disc. The farther the tires moves out the disc, the faster the machine goes. I even have an old 29 series Singer I was thinking about experimenting on.

I have looked at a lot of big machines, never owned one really but it always looks like a problem to me. My brother in law bought a big industrial Juki sweat shop machine and quickly found out it was totally unsuitable for what he wanted, way too fast. I have been thinking a lot about a way to control the speed on one. A rheostat controlled motor is one choice but they never seem to have much power on slow. Another Idea I had would be a sort of transmission that had a rubber tire running on a spinning disc. The farther the tires moves out the disc, the faster the machine goes. I even have an old 29 series Singer I was thinking about experimenting on.

Why is everyone so afraid of actually learning how to use the sewing machine? When I first learned, there were no such things as servo motors so you either learned to slip the clutch motor or you couldn't sew with the machine.

Theoretically, a rheostatically controlled motor would work on a sewing machine because the slower you go, the more torque is produced. In practice, however it would not be very economical to do it that way. The motor would need to be a DC motor, because running an AC motor at slow speeds all the time would burn the motor up because it couldn't cool itself. They don't use DC motors because they are way more expensive than AC motors. The reason they used AC clutch motors on them in the first place is because, for a long time, it was the best and also the cheapest way to power the machine. Anyone who is any good at sewing can make a clutch motor do anything a servo can. The reason I switched to servos is because I hated listening to the sewing machine run when I wasn't pressing on the foot pedal, and the savings in electricity were so great.

The easiest way to slow down a sewing machine is to put a very small pulley on the motor, which will cut top speed by at least 1/2. If you also use a servo motor you can get the motor to absolutely creep. The servo is a constant torque device, so it has low end torque and is the simplest, and cheapest, way to get it all in one package.

You also need to practice with the machine. They don't just give you a driver's license when you're 16, you need driver's ed and experience too, just like anything else that is a learned skill.

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No one lives forever, the trick is creating something that will.
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What Dan said. I know he's a pro that's been sewing since Christ was a corporal, but if I can slow down a machine and learn to control it having never touched a sewing machine in my life, anyone can - believe me.

Inventing and modifying is great, and it has its place, but in this case the research and development has already been done for you - just a simple belt and pulley swap will give you the result you'll need with no loss of power, torque, or other modifications to the machine or table at all. It literally took me 15 minutes and 3 tools to do this modification - a screwdriver, Allen wrench, and pulley puller. When I said I did it for less than $20, I meant a lot less - I think the pulley was $4, and the belt was another $5 or $6.

Oh, and get ready for it, bentwings - you ain't seen nothin' yet. My grandfather told me years ago that if you have a truck or can weld, you'll always have friends - add "can sew upholstery" to that list. Friends you never knew you had will come out of the woodwork with all kinds of projects for you. While you're learning to use the machine, also learn that your labor is a valuable commodity. One guy I didn't even know thought $20 would be a good price for me to replace his headliner. He still thinks that, and he still needs a headliner. I give my friends a huge discount (they buy the materials I tell them to buy and I cut my labor charge up to 90%,) but nobody rides for free - well, with a few exceptions. I'll do a quick seam repair or some other trivial thing for free. I'm not a total... well... insert your own adjective here...

Haha that's funny. I get that all the time with my TIG welding. " It's only a small repair......won't cost much." Or "I gotta small miss while cruising...think you can fix it.".....obviously free after spending all afternoon on a problem that isn't there inthe first place. My dad was in marketing and sales all his life and he told me friends and relatives are your worst customers.

I just got sucked in building and $800 dry sump tank for about half that. It's going to be a loser but the guy is a nice guy and I'll get it back when I bring my dually in to his store for oil changes. (They are not fun)

The headliner thing is interesting. That will be my first real project after I get some time on this thing. I have already made all the roof bows twice out of oak. I have "upholstered" them 4 times with plastic (different thickness) to see just what is involved with "hanging" it. My car is a 'plastic' car so there is nothing to mount the headliner on. Rods are much more difficult to mount but probably easier to install. I don't know...lack of experience. I did make one attempt to make rod mounts after going and looking at a steel car. So far the best of the headliner mounts I've seen for plastic cars is oak bows and staple the listing to the bows. I can see this will be very difficult to do by myself. If it is done with vinyl (not too stretchy) it will requre very accurate measuring, cutting and sewing to match up 7 bows plus the head board and rear tack rail..
The first go around will be with standard headliner material.

As it turns out one of the most respected glass car makers is now offering roof bow kits so apparently there is some demand. I've seen even steel cars done with this method too. Once I get the 3rd set installed I'll post pictures.

You also need to practice with the machine. They don't just give you a driver's license when you're 16, you need driver's ed and experience too, just like anything else that is a learned skill.

This is true and I practice every chance I get. When I first started, I couldn't sew a straight line. Now I can and do it as often as possible in order to maintain my skills. Why do law enforcement officers go to firing ranges? To make sure they still have control over their tool of the trade. I have friends who shoot 3X a week in order to stay sharp. Now in this world, do you want to screw up a $500 piece of leather because you have not been practicing? I don't think so.

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